Work is set to begin on a £1.5m transformation of London’s oldest free aquarium.

The Horniman Museum Aquarium, which has been in operation for more than 100 years, is moving down into the museum’s basement and being redeveloped into seven distinctive zones.

The zones will take visitors on an interactive journey from the aquarium’s Victorian origins through British pond life and coastal areas to a Fijian coral reef and a South American rainforest. Atmospheric sounds and smells will also be introduced.

The project has received a £1.1m grant from ReDiscover, the science centre renewal fund, and the museum has launched a fundraising campaign to raise the remaining £400,000.

The development – which will include 200sq m (2,150sq ft) of visitor space and a further 200sq m of laboratories and food preparation areas – has been designed through a collaboration between the aquarium’s manager, Kerwin Porter and international habitat designers and biologists alongside Manchester-based architects Buttress Fuller Alsop Williams.

The original aquarium has now closed and construction work in the basement – which formerly housed the Horniman Library – is set to begin by the end of the month.

A spokesperson for the aquarium said the new attraction is designed to educate visitors about the natural world and also about the growing threat to aquatic environments. “The new aquarium will serve as a proactive forum for visitors to contribute to local and global conservation efforts,” he said.

Once the aquarium opens – scheduled for the spring of 2006 – it will continue to offer free entry to the public. Details: www.horniman.ac.uk or +44 (0)20 8699 1872